If you don't think that's enough, Mercedes will provide you with an AMG Performance Package for an additional 12,530; this ramps up power and torque by 26bhp and 74lb ft respectively.

It also brings a limited-slip differential and raises the top speed from 155mph to 186mph.

SL63 AMG has a twin-turbo V8 engine that develops up to 556bhp

The 0-62mph sprint takes just 4.2 seconds with the AMG Performance Package, or 4.3 seconds without it. We suggest you don't indulge in these antics anywhere near built-up areas, because the thunderous bellow from the exhaust when the engine is working hard can rattle windows from half a mile off.

Even when you're just coaxing it around, the SL63's acceleration is simply brutal, and the engine's mammoth torque means it pulls hard from just about anywhere in the rev range.

Cabin features a double-stitched leather dashboard and feels every inch the premium product

Despite its considerable length and width, the SL63 turns into corners sharply and grips tenaciously, while the electronic aids intervene subtly if you push too hard.

Put the suspension in its 'Sport' setting and corners are dispatched with virtually zero body lean. As impressive as this is, 'Comfort' mode is far better suited to the SL's character; for all its sporting pretensions, the SL63 is still at its best as a luxurious touring convertible.

Aside from the occasional clunk through the back end, the car rides with a subtlety that would shame many a luxury saloon. It's utterly stable and composed on the motorway, too.

With the roof down and the side windows and wind deflector up, there's little wind buffeting in the cabin. Raise the roof and you're cocooned from wind and road noise as well as in any luxury coupe, although the engine never completely fades into the background.

What's the 2012 Mercedes SL63 AMG like inside?

The SL's cabin features a double-stitched leather dashboard with metallic and carbonfibre inserts, and slick switchgear, so it feels every inch the premium product.

For all its sporting pretensions, the SL63 is still at its best as a luxurious touring convertible

You won't feel short changed by the equipment you get, either; heated leather seats, sat-nav and a six-disc DVD changer are all standard, although it's a little disappointing that you need to fork out 525 for the electronically controlled wind deflector.

You can also choose from a vast array of other optional extras, including an Airscarf neck-heating system, cooled seats and a reversing camera.

There's plenty of space for two in the SL and the standard electric seat adjustment makes it easy to find a comfortable position. However, it's quite difficult to judge where that long nose ends when you park the car.

The optional glass roof adds to the feeling of space and is available with Magic Sky Control (a 2610 option) that lets you switch the roof panel from transparent to opaque at the touch of a button.

The SL's metal roof can be folded back into the boot in less than 20 seconds. Your luggage capacity shrinks from a very accommodating 504 litres to just 364 litres when you drop the top, but the space that's left is wide enough to take a set of golf clubs.

Should I buy one?Even though this new car is 30% more efficient than the outgoing model, it still returns just 28.5mpg, and that's on a good day. Make the most of the performance and chances are you'll halve that figure.

With this much power on tap, you'll also face hefty bills for insurance and tyres, but if you can afford an SL63 AMG in the first place, you probably won't lose too much sleep about any of the above.

What you might want to stop and consider is that for almost 40,000 less you can have the SL350, which is even more comfortable and still anything but slow. In our opinion, it's a far better choice if you're after an elegant coupe-cabrio.